Traditionally, animals which are housed within a dwelling intended primarily for human habitation are provided a pan or receptacle in which to relieve themselves. This receptacle is normally filled with a granular material such as clay, which is intended to absorb urine as well as provide the pets, especially cats, with a medium in which to dig and/or bury their excrement. One of the major problems with systems of this type is that the granular material, i.e., the litter, gets filled with excrement, particularly feces. As a result, most pet owners dispose of the litter on a frequent and regular basis in order to dispose of the excrement without directly handling it. In most instances the litter is disposed of long before its useful life as an absorbent has been exhausted. Additional problems with traditional systems of the aforementioned type are the inconvenience, mess and health hazard associated with the disposal operation.
Numerous attempts have been made to address these problems, with limited success. U.S. Pat. No. 4,802,442 issued to Wilson on Feb. 7, 1989 and U.S. Pat. No. 4,817,560 issued to Prince et al. on Apr. 4, 1989 both describe durable removable screens which are intended to filter the fecal excrement from the litter for separate disposal. In both these cases the disposal of the fecal excrement is still a problem, since it must be removed from the filtering device for disposal. The filtering device must then be either reused in a soiled condition or cleaned. In either case, the filter must be reinserted into the litter for subsequent use. These steps involve several handling operations, all of which involve significant contact with the soiled filter and/or fecal excrement. Needless to say, most pet owners find this highly undesirable.
U.S. Pat. No. 3,796,188 issued to Bradstreet on Mar. 12, 1974 and U.S. Pat. No. 4,096,827 issued to Cotter on June 27, 1978 describe disposal systems which are intended to minimize contact with both the filtering device and the fecal excrement by, respectively, sliding a cover or flipping the receptacle, whereby the litter is filtered and the fecal excrement is removed. One significant drawback of each of these devices is their complexity of construction. In addition, these devices still embody a soiled filter which must be cleaned, thereby necessitating significant human contact to complete the disposal operation.
Several issued U.S. Patents disclose a disposable filter which is used in an attempt to overcome the human contact problem previously described. U.S. Pat. No. 4,312,295 issued to Harrington on Jan. 26, 1982 describes a filter inserted into a litter pan before the litter is added. The filter is formed by providing a multiplicity of slits in a web. In that execution the slits open under the weight of the litter when the filter is lifted from the pan to facilitate the filtering operation. U.S. Pat. No. 3,809,013 issued to Rigney et al. on May 7, 1974 and U.S. Pat. No. 4,784,082 issued to Wolfe on Nov. 15, 1988 both describe similar filtering devices. These filtering devices comprise impervious webs having partially perforated, but unopened areas which open to form apertures under the weight of the litter when the filter is lifted.
A significant problem with filtering systems of the aforementioned type is that due to the fact that a pet scratching in the litter may come in direct contact with the filtering media while the filtering system is in use, the filtering media employed must normally be selected based on a compromise between strength and filtering ability. This compromise is necessary because the hole or aperture size in the filtering media must be selected based on the comparative size difference between the litter and the anticipated size of the fecal excrement. Once the hole size has been determined, the only way in which adequate strength can be provided is by properly adjusting the hole spacing. For fast, efficient filtering of the fecal excrement from the litter, a minimum spacing between adjacent holes is desirable. However the strength required to resist damage when the pet digs typically precludes extremely close hole spacing. Thus the filtering operation normally takes a relatively long time to carry out and often requires shaking of the filtering media to keep the filtering operation from ceasing altogether before it is complete.
U.S. Pat. No. 4,615,300 issued to McDonough on Oct. 7, 1986 attempts to address this issue by employing a stacked filtering system comprising a highly porous mesh having an underlying impervious flap. The excrement and/or litter is prevented from soiling the underlying filtering units contained within the stack by the impervious flap underlying each of the porous mesh members. While the McDonough system allegedly provides more efficient filtering, access by the pet to the uppermost highly porous mesh can be had as a result of the pet's digging action. The natural instinct of animals, especially cats, to dig could thus result in the uppermost filter member being substantially ruptured and rendered ineffective at properly filtering fecal excrement from the litter when the filter is lifted to perform the intended separating operation.
Another problem which may occur with structures of the type disclosed by McDonough is that during the course of digging, the cat's claws could become entangled in the filter. At best, this may lead to scattering of the litter material about the room or at worst, cause injury to the cat.
It is an object of the present invention to provide a litter filtering and disposal system which overcomes the various problems associated with prior art litter filtering and disposal systems.
It is another object of the present invention to provide a simple, fast and inexpensive means to remove fecal matter from the granular material which is used as the litter.
Another object of the present invention is to provide a convenient, inexpensive way to dispose of animal excreta, both solid and liquid, which is adaptive to current consumer habits and practices.
Another object of the present invention is to provide a hygienic means for collecting and disposing of animal excreta without the need for human contact with either the excreta or the litter and without the need to prematurely dispose of the litter.
It is still another object of the present invention to provide a filtering and disposal system capable of meeting the widely differing needs of pet owners, i.e., some pet owners feel that daily cleaning is necessary while others allow the receptacle to stand for days or even weeks without taking steps to clean it.